Contribution of presystemic hepatic extraction to the low oral bioavailability of green tea catechins in rats
| Autor: | Nathan D. Anavy, Yan Cai, H-H. Sherry Chow |
|---|---|
| Rok vydání: | 2002 |
| Předmět: |
Male
Membrane permeability Flavonoid Pharmaceutical Science Biological Availability Pharmacology Epigallocatechin gallate complex mixtures Catechin chemistry.chemical_compound First pass effect Oral administration Animals Rats Wistar chemistry.chemical_classification Dose-Response Relationship Drug Tea Portal Vein food and beverages Bioavailability Rats chemistry Biochemistry Liver Polyphenol Area Under Curve Injections Intravenous Indicators and Reagents |
| Zdroj: | Drug metabolism and disposition: the biological fate of chemicals. 30(11) |
| ISSN: | 0090-9556 |
| Popis: | Green tea and green tea catechins have been shown to possess potent cancer-preventive activities in rodent cancer models. At present, epidemiological evidence of the protective effect of green tea consumption against the development of human cancers is not conclusive. Oral bioavailability of green tea catechins has been shown to be low in animals and possibly in humans. This study is designed to determine the contribution of first-pass hepatic elimination to the low oral bioavailability of green tea catechins. Green tea catechin mixture was dosed to rats by intravenous or intraportal infusion. Blood samples were collected after dosing and analyzed using high-performance liquid chromatography with the coulometric electrode array detection system. The systemic clearance of epigallocatechin gallate (EGCG), epigallocatechin (EGC), and epicatechin (EC) was 8.9, 6.3, and 9.4 ml/min, respectively. The steady state volume of distribution ( V ss ) of EGCG, EGC, and EC was 432, 220, and 187 ml, respectively. We found that high percentage of green tea catechins escaped first-pass hepatic elimination, with 87.0, 108.3, and 94.9% of EGCG, EGC, and EC, respectively, available in the systemic blood following intraportal infusion. Our results suggest that factors within the gastrointestinal tract such as limited membrane permeability, transporter mediated intestinal secretion, or gut wall metabolism may contribute more significantly to the low oral bioavailability of green tea catechins. |
| Databáze: | OpenAIRE |
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